1. Field of the Invention
This invention relates to a polymeric laminate material containing printed matter which may be thermoformed into various shapes.
2. Background of the Invention
In general, laminated materials for ultimate use as containers, trays, etc. are known in the art.
For example, U.S. Pat. No. 2,974,057 discloses plasticized films comprising a rigid polymeric self-supporting sheet of plasticized polyvinyl chloride polymer and a coating of a cellulosic polymer and an acrylate. The rigid self-supporting sheet material may optionally contain printed matter.
U.S. Pat. No. 3,356,560 discloses a heat-formable sheet material comprising a core layer, a protective skin layer on one side of the core and an outer coating layer on the opposing side of the core. The core layer of this patent comprises a gum-plastic, such as a rubber or a resin based on acrylonitrile, butadiene, and styrene. The protective skin layer is a mixture of a butadiene-acrylonitrile rubber and a polyvinyl chloride resin and the outer coating layer is disclosed as being a blend of a polyvinyl halide polymer, styrene and methyl methacrylate.
U.S. Pat. No. 3,562,095 discloses a synthetic resin laminate comprising a center core layer of an unsaturated polyester with one or more multifunctional monomers and a second layer comprising a synthetic resinous thermoplastic polymer bonded to at least one face of the core. The resinous thermoplastic polymer used in the laminate of this patent may comprise polyvinyl chloride, chlorinated polyvinyl chloride, chlorinated polyethylene and related materials.
U.S. Pat. No. 4,289,817 discloses lined, hollow plastic articles and a method of making the same. The articles of this patent comprise an outer pressure molded first portion of a transparent plastic material and a drawn inner second portion of a plastic material. The inner material may be any one of acetal polymers, polyolefins, etc., while the outer thermoplastic layer must be transparent or translucent and may comprise polyolefins, polystyrene, etc. This patent is related to U.S. Pat. Nos. 3,717,544; 3,719,735; 3,787,157 and 3,939,239.
U.S. Pat. No. 4,442,158 discloses a plastic laminate adapted for use as a food package comprising an exterior polypropylene layer, a middle polyvinylidene chloride layer and an inner ionomer resin layer. U.S. Pat. Nos. 4,443,507 and 4,873,137 disclose examples of laminated polymeric materials which comprise layers reinforced with fibers and glass flakes, respectively.
Although laminated polymeric materials are known in the art, the known materials have demonstrated drawbacks, such as difficulties with or a complete inability to print the material, delamination of the layers, etc. Therefore, there is a need for a thermoformable laminate material which is satisfactory in all respects.
Another problem of known polymeric laminate articles was the inability to precisely print information and designs on the articles. For example, the plastic articles discussed in the patents noted above had markings randomly located with respect to the article shape. This is disadvantageous, for example, in the food packaging art wherein markings such as a bar code, a trademark, a list of ingredients, depictions of food products, etc., are desired to be precisely located on each package to produce an attractive and easily marketable package. The ability to specifically register the markings with respect to predetermined locations on the thermoformable articles is a very desirable feature in a thermoformable plastic laminate article.